Simulation and kinetic modeling of supercritical water gasification of biomass

In this article, kinetic study is performed to construe the kinetics of gasification of model biomass compounds in supercritical water (SCW) in the presence of catalyst for hydrogen production using the mechanistic models developed applying Langmuir-Helshinwood-Hougen-Watson (LHHW) and Eley-Rideal (ER) procedure. Besides, two types of model biomass are used to perform simulation of SCWG for producing H-2 using the Aspen Plus. Glucose is used for both kinetic study and simulation. As well, further simulation is performed using hydroxymethyle furfural and phenol mixture. A better justification is obtain between the simulation results and data from literature. Higher temperature shows better hydrogen yield whereas higher concentration of biomass shows decreased hydrogen production. None of the gasification efficiency, product yield and carbon conversion efficiency is significantly affected by pressure variation. It is found that gasification efficiency is higher than 100%, which means SCW actively takes part in the reaction as an important reactant. Higher temperature favor carbon conversion efficiency (CCE). With the increase in concentration, CCE increases for glucose. However, the mixture of phenol and hydroxymethyl furfural (HMF) showed a declining trend with an increase in biomass concentration. Among the proposed mechanistic models, three models converged. However, an ER based model described as the dissociation of adsorbed glucose through Retro-Aldol reaction is found to be the rate determining step with an average absolute deviation 10.6%. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.